Gust Load Alleviation of Flexible Aircraft

Concerns about aircraft gust disturbance have increased not only because of the design cases that are not primarily structural but also because of gust influence on aircraft handling qualities and flight controllability. Load alleviation system duty is reducing loads caused by a gust on aircraft. Using active control when crossing gust causes alleviation of loads on aircraft and improves ride quality. In this paper gust response of a flexible aircraft has been simulated by using the Lagrange equation and quasi-steady aerodynamics. Wing has been considered as flexible and other parts have been considered rigid. Two degrees of freedom in pitch and plunge of rigid mode have been considered and the elastic wing has been modeled as a beam with torsion and bending. Gust responses with different profiles have been analyzed. Then by using elevators and aileron gust loads have been reduced. Feedback control has been used to decrease the pitch and heave acceleration of the aircraft. Closed and open-loop response to gust has been compared and it has been shown that pitch oscillations have been damped very well by elevator. Then by using elevators and flaperon gust loads have been reduced by using neural networks adaptive controller and classic controller. Comparison has been made between closed-loop and open loop response to gust.